1. Field of the Invention
The present invention relates to a surface treatment composition for treating a metal wiring-including surface of a semiconductor substrate, a surface treatment method, and a method for manufacturing a semiconductor device.
2. Description of the Related Art
With an increase in the integration of semiconductor devices, a semiconductor device manufacturing process has become complicated. In such a complicated semiconductor device manufacturing process, a semiconductor substrate may be exposed to an oxygen-containing atmosphere during a period after chemical mechanical polishing and before the following process. In such a case, when a semiconductor substrate surface has a metal wiring portion of copper or the like, the metal wiring portion is oxidized. It has been known that when the metal wiring portion is oxidized, the electrical properties of a semiconductor device to be obtained deteriorate.
Examples of methods for suppressing oxidation of metal wiring portions include a method including holding a semiconductor substrate in inactive gas or the like during a period after chemical mechanical polishing and before the following process. In former techniques, oxidation of metal wiring is required to be suppressed by performing such a strict process control.
When the metal wiring portion is a copper wiring portion, a convex-shaped unusual-oxidation portion having the height of 10 to 50 nm generates in the copper wiring portion to deteriorate the flatness of the wiring portion, resulting in a problem of reduced yields. Therefore, techniques for suppressing the oxidation of metal wiring portions of copper or the like by a simple method have been demanded.
As the method for suppressing oxidation of a copper wiring portion, a method for suppressing the oxidation-reduction potential of a treatment agent to be used in a surface treatment process of a surface to be polished after chemical mechanical polishing has been proposed (e.g., Patent Document 1)    Patent document 1: JP-A 2007-291505.